Field of Invention
Various embodiments of the present disclosure relate to a memory device and a method of operating the memory device and, more particularly, to a read operation of a memory device including a memory block on which a partial erase operation is performed.
Description of Related Art
Memory devices may be classified into a volatile memory device and a nonvolatile memory device.
The nonvolatile memory device has relatively low write and read speeds compared to the volatile memory device, but may maintain data stored therein even if the supply of power is interrupted. Therefore, nonvolatile memory devices are used widely in portable electronic devices for storing data that need to be maintained regardless of whether or not power is supplied to the memory device at all times. Examples of nonvolatile memory devices include a Read Only Memory (ROM), a Mask ROM (MROM), a Programmable ROM (PROM) an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a flash memory, a Phase change Random Access Memory (PRAM), a Magnetic RAM (MRAM), a Resistive RAM (RRAM), a Ferroelectric RAM (FRAM), etc. depending on the scheme for storing data.
The flash memory device may be formed either in a two-dimensional (2D) structure in which cell strings are arranged horizontally on a semiconductor substrate or in a three-dimensional (3D) structure in which cell strings are arranged vertically on a semiconductor substrate. 3D memory devices are devised to overcome a limitation in the degree of integration of the 2D memory devices, and may include a plurality of memory cells stacked vertically on a semiconductor substrate. 3D memory devices are relatively new and substantial research and development efforts are spent in improving their performance characteristics.